Comparison of 2 moxifloxacin regimens for preoperative prophylaxis: Prospective randomized triple-masked trial Part 1: Aqueous concentration of moxifloxacin Abhay R. Vasavada, MS, FRCS, Devarshi Gajjar, PhD, Shetal M. Raj, DO, MS, Vaishali Vasavada, MS, Viraj Vasavada, MS PURPOSE: To evaluate the aqueous concentration of moxifloxacin following 2 dosing regimens of topically administered moxifloxacin hydrochloride ophthalmic solution 0.5% (Vigamox). SETTING: Iladevi Cataract & IOL Research Centre, Ahmedabad, India. METHODS: In this prospective randomized triple-masked clinical trial, 156 patients having cataract surgery were randomly assigned to 1 of 2 regimens of preoperative prophylaxis. In Group A (n Z 76), Vigamox was instilled 4 times a day 1 day before surgery plus 1 drop 2 hours before surgery (total of 5 drops). In Group B (n Z 76), Vigamox was first instilled 2 hours before surgery and then every 15 minutes for 1 hour (total of 5 drops). In both groups, aqueous samples (0.1 mL) were collected within 2 hours of the first instillation on the day of surgery and stored at 80  C. The antibiotic concentration in all aqueous aspirates was determined using high-performance liquid chromatography. Data were analyzed using the Kolmogorov-Smirnov t test; 95% confidence intervals (CIs) were calculated. RESULTS: The mean aqueous humor concentration of moxifloxacin was 1.58 mg/mL G 0.80 (SD) in Group A and 2.05 G 0.72 mg/mL in Group B (P<.0001; 95% CI, 0.72 to 0.22). CONCLUSIONS: Both dosing regimens produced substantially higher aqueous concentrations than the known minimum inhibitory concentration for Staphylococcus epidermidis. Topical moxifloxacin administered 2 hours before surgery achieved significantly higher aqueous concentrations than topical moxifloxacin administered 1 day before surgery with 1 drop given on the day of surgery. J Cataract Refract Surg 2008; 34:1379–1382 Q 2008 ASCRS and ESCRS Based on anecdotal evidence, topical fluoroquinolone antibiotic agents are widely used as an adjunct to povi- done–iodine for prophylaxis before intraocular proce- dures. 1 The goals of prophylactic antibiotic treatment before cataract surgery are to achieve the optimal antibi- otic concentration in corneal and aqueous humor tissue at the time of surgery and to reduce the bacterial popu- lation on the conjunctiva and eyelids. To achieve these goals, antibiotic prophylaxis is started a few days before surgery, 2–5 on the day of surgery a few hours preopera- tively, 4,6,7 or using a combination of these. 1,2,5,8,9 Several studies 5,8,10 have compared fourth-genera- tion fluoroquinolones with other antibiotic agents. Several studies have evaluated moxifloxacin, a fourth-generation fluoroquinolone, using different regimens. Some of the studies 2–7 assessed the moxiflox- acnin concentration in the aqueous humor and others, 8 the residual bacterial population after moxifloxacin in- stillation. The findings cannot be extrapolated as the antibiotic regimens are different in each study. We therefore sought to compare the penetration and effi- cacy of moxifloxacin hydrochloride ophthalmic solu- tion 0.5% (Vigamox) in 2 standard regimens. Here, we present the results of part 1 of the study, which eval- uated the penetration of Vigamox into the aqueous hu- mor of patients. The goal was to determine whether administering this preservative-free fluoroquinolone on the day of surgery confers benefits over a regimen in which instillation begins the day before surgery. PATIENTS AND METHODS This prospective randomized triple-masked clinical trial comprised patients having surgery for uncomplicated age- related cataract. It was conducted at a clinical practice at Q 2008 ASCRS and ESCRS Published by Elsevier Inc. 0886-3350/08/$dsee front matter 1379 doi:10.1016/j.jcrs.2008.04.027 ARTICLE